1. Field of the Invention
Embodiments of the present invention relate to an organic light emitting display device and a method for driving the same. More particularly, the present invention relates to an organic light emitting display device to compensate degradation of an organic light emitting diode, and a method for driving the same.
2. Discussion of the Related Art
Due to recent developments in multimedia, there is an increasing demand for a flat panel display. In order to satisfy this increasing demand, various flat panel displays such as liquid crystal display device, plasma display panel, field emission display device and organic light emitting display device are practically used. Among the various flat panel displays, the organic light emitting display device drawn the attraction as a next-generation flat panel display because of its advantages of rapid response speed and low power consumption. In addition, the light emitting display is self-emitting, whereby the light emitting display does not cause a problem related with a narrow viewing angle.
Generally, the organic light emitting display device may include a display panel having a plurality of pixels, and a panel driver for driving the respective pixels so as to make the respective pixels emit light. In this case, the pixels are respectively formed in pixel regions, wherein the pixel regions are defined by crossing a plurality of gate lines and a plurality of data lines.
Referring to FIG. 1, each pixel may include a switching transistor (Tsw), a driving transistor (Tdr), a capacitor (Cst), and an organic light emitting diode (OLED).
As the switching transistor (Tsw) is switched by a gate signal (GS) supplied to a gate line (GL), a data voltage (Vdata) supplied to a data line (DL) is supplied to the driving transistor (Tdr).
As the driving transistor (Tdr) is switched by the data voltage (Vdata) supplied from the switching transistor (Tsw), it is possible to control a data current (Ioled) flowing to the organic light emitting diode (OLED) by a driving voltage (VDD).
The capacitor (Cst) is connected between gate and source terminals of the driving transistor (Tdr), wherein the capacitor (Cst) stores a voltage corresponding to the data voltage (Vdata) supplied to the gate terminal of the driving transistor (Tdr), and turns-on the driving transistor (Tdr) by the use of stored voltage.
The organic light emitting diode (OLED) is electrically connected between the source terminal of the driving transistor (Tdr) and a cathode electrode applied with a cathode voltage (VSS), wherein the organic light emitting diode (OLED) emits light by the data current (Ioled) supplied from the driving transistor (Tdr).
Each pixel of the organic light emitting display device according to the related art controls an intensity of the data current (Ioled) flowing to the organic light emitting diode (OLED) by the driving voltage (VDD) through the use of switching of the driving transistor (Tdr) according to the data voltage (Vdata), whereby the organic light emitting diode (OLED) emits light, thereby displaying an image.
FIG. 2 is a graph illustrating luminance change of the related art organic light emitting display device in accordance with the lapse of time.
As shown in FIG. 2, a degradation speed becomes faster according to the increase of driving time in the organic light emitting diode (OLED), to thereby deteriorate the luminance characteristics. In the organic light emitting display device according to the related art, it is difficult to display images with uniform luminance due to the degradation of the organic light emitting diode (OLED).